176 lbs though, that's something to be concerned about, can he be expected to tackle 220 lb running backs?

That is a concern. Make you wonder about his long term durability. Definitely has mega speed. You never know. Might not be able to take the pounding from big backs. Then again he may become a star. Time will tell. If it's the latter let's hope it's in a Steeler uniform.

yea 176lbs is to light. the bigger WR's would toss him aside at the line and i doubt he would be able to help in the run game. he should of tried to add some weight before the combine bur if he got up to 200lbs i doubt he would still run a 4.28